A new type of display panel having memory is described in U.S. Pat. No. 4,386,348 of George E. Holz and James A. Ogle. The panel comprises a gas-filled envelope including a layer of D.C. scan/address cells and a layer of quasi A.C. display cells. The scan cells are arrayed in rows and columns, and the display cells are arrayed in corresponding rows and columns. The scan cells are scanned and turned on column-by-column by operation of their electrodes while sustain signals are simultaneously being applied to the display cells, and the same electrodes are used to transfer information from selected scan cells to the associated display cells where glow is sustained by the sustainer signals. The cells which are energized in the entire panel, by this routine, display a stationary but changeable message.
It is desirable, for some applications, to be able to dim a panel of the type described above, and dimming can be achieved by lowering the frequency of the sustainer signals. However, if this is done, the writing of new information at the lower sustainer frequency may be slow and flicker may occur.